Diagnostic Potential of Urinary ACP1 in Bladder Cancer Revealed by Integrative Omics Analysis

Bladder cancer is a common malignancy with a high recurrence rate, often requiring repeated invasive procedures for diagnosis and monitoring. Although cystoscopy remains the gold standard for diagnosis, it is associated with patient discomfort and procedural risks. Non-invasive urine-based molecular assays have attracted attention as alternatives, but their diagnostic performance remains suboptimal. This study aimed to identify bladder cancer-specific biomarkers detectable in tissue and urine samples. An integrative analysis of a urinary proteomic dataset (PXD044896) and two transcriptomic datasets (GSE52519 and GSE27448) was performed, identifying five candidate genes commonly upregulated in bladder cancer. Among these, ACP1 was specifically overexpressed in bladder cancer compared to other urological cancers based on The Cancer Genome Atlas data. Moreover, ACP1 overexpression in bladder cancer patients was confirmed in two independent Gene Expression Omnibus datasets derived from urine (GSE68020) and tissue (GSE166716) samples, and further validated in high-grade tumors using GSE32894 and immunohistochemical images from the Human Protein Atlas. Lastly, high ACP1 expression was associated with poor overall survival in papillary and non-papillary subtypes of bladder cancer. These findings support the potential of ACP1, which is detectable in tissue and urine, as a bladder cancer-specific biomarker for non-invasive diagnosis and prognosis.